Leslie Brandon Shaw

Highly nonlinear As–S–Se glasses for all-optical switching

We have synthesized a series of chalcogenide glasses from the As-S-Se system that is designed to have strong nonlinearities. Measurements reveal that many of these glasses offer optical Kerr nonlinearities greater than 400 times that of fused silica at 1.25 and 1.55mum and figures of merit for all-optical switching greater than 5 at 1.55mum .

Mid-wave IR and long-wave IR laser potential of rare-earth doped chalcogenide glass fiber

The mid-wave IR and long-wave IR laser potential of rare-earth ions in chalcogenide glass fiber is reviewed. Spectroscopic data for the mid-wave and long-wave IR transitions for Pr/sup 3+/, Dy/sup 3+/, and Tb/sup 3+/ in chalcogenide glass is presented and used as a basis for discussion of laser potential in these glasses.

A 7-/spl mu/m praseodymium-based solid-state laser

We report the first demonstration of laser emission from the /sup 3/F/sub 3/ to /sup 3/F/sub 2/ transition in the rare earth praseodymium. This new 7-/spl mu/m solid-state laser operates with an optical efficiency of 2.3% at 293 K and 10% at 150 K using an upconversion pumping mechanism. A discussion of the dynamics in this new laser material is included.

A 7-{micro}m praseodymium-based solid-state laser

We report the first demonstration of laser emission from the /sup 3/F/sub 3/ to /sup 3/F/sub 2/ transition in the rare earth praseodymium. This new 7-/spl mu/m solid-state laser operates with an optical efficiency of 2.3% at 293 K and 10% at 150 K using an upconversion pumping mechanism. A discussion of the dynamics in this new laser material is included.

Modeling of Cascade Lasing in Dy : Chalcogenide Glass Fiber Laser With Efficient Output at 4.5

The performance of a continuous-wave Dy:GeAsGaSe chalcogenide glass fiber laser operating on the ⁶H_11/2 rarr ⁶H_13/2 transition at 4.2-4.7 mum is studied using numerical modeling. A double-clad fiber geometry is assumed, with direct pumping of the ⁶H_11/2 level at 1.7 mum. It is shown that simultaneous lasing on the ⁶H_13/2 rarr ⁶H_15/2 transition serves to effectively depopulate the ⁶H_11/2 level and significantly improve the efficiency and power scalability. A slope efficiency of 0.16 is calculated when the fiber loss is 1 dB/m. For efficient operation, it is necessary to keep the fiber loss below ap5 dB/m.

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We report the first demonstration of high bit rate signal processing by a fiber-based photonic wire. We achieve 160 Gb/s demultiplexing via four wave mixing in a 1.9 microm diameter photonic wire tapered from As(2)S(3) chalcogenide glass single mode fibre, with very low pump power requirements ( < 20 mW average power, 0.45 W peak power), enabled by a very high nonlinearity (gamma approximately 7850 W(-1) km (-1) ) and greatly reduced dispersion.

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We characterize the nonlinear propagation of picosecond pulses in chalcogenide As(2)S(3) single-mode fiber using a pump-probe technique. The cross-phase modulation (XPM)-induced sideband broadening and stimulated Raman scattering (SRS)-induced sideband amplification are measured in order to map out the Raman gain spectrum of this glass across the C-band. We extract the Raman response function from the Raman gain spectrum and determine the power and polarization dependence of the SRS. In contrast to previous work using As(2)Se(3) fiber, we find that the As(2)S(3) fiber does not suffer from large two-photon absorption (TPA) in the wavelength range of the telecommunications band. We achieved a 20 dB peak Raman gain at a Stokes shift of 350 cm(-1) in a 205 mm length of As(2)S(3) single-mode fiber. The Raman gain coefficient is estimated to be 4.3x10(-12) m/W and the threshold pump peak power is estimated to be 16.2 W for the 205 mm As(2)S(3) fiber. We also demonstrate that we can infer the dispersion of the As(2)S(3) fiber and justify the Raman response function by comparing simulation and experimental results.

High bit rate all-optical signal processing in a fiber photonic wire

The spectral properties of Pr 3+ doped BaInGaGeSe chalcogenide glasses are reported. Absorption spectra, emission spectra, and lifetimes of the lower lying manifolds have been measured. Radiative transition rates are calculated and compared with measured experimental lifetimes. The strong mid-IR emission and spectral properties of this glass make this glass a strong candidate for lasers, amplifiers, and high brightness sources in the mid-IR.

Characterization of picosecond pulse nonlinear propagation in chalcogenide As 2 S 3 fiber

Chalcogenide glass optical fibers were fabricated into functional apertured probes for near field scanning infrared microscopy. Probe fiber tips were chemically etched and aluminum coated for the purpose of simultaneously collecting near field shear force and optical signals. Surface topography and infrared optical reflectivity data were obtained using the tips in a scanning near field microscope while illuminating an integrated microcircuit with the output from a free electron laser operating at a λ of 4.7 μm. Approximately 25 nm topographical and 100 nm optical lateral resolution were observed.

Spectroscopy of the IR transitions in Pr 3+ doped heavy metal selenide glasses

We present a model for optical amplification at 1.3 /spl mu/m using Dy/sup 3+/ in fibers made from a low phonon energy glass, based on GeAsSe. This model uses in-band pumping at 1.28 /spl mu/m, takes into account the spectral distribution of amplified spontaneous emission, and allows for bottlenecking of excited ions into the intermediate states in Dy as well as the excited state absorption (ESA) from those levels. Using data obtained from spectroscopic measurements and Judd-Ofelt calculations, our model shows that very high gain (>30 dB) is possible in short lengths (40-100 cm) of fiber. Given the very high quantum efficiency of the radiative transition in this glass, we show that bottlenecking and ESA should not have a significant impact on device performance. We also predict that devices made from this fiber should have a very high tolerance to the passive loss of the fiber.